The present invention relates generally to a mechanical injection pump governor. More particularly, the governor has a negative adapting device which functions from the lower speed range up to the full-load characteristic curve of a supercharged diesel engine for automatically matching the delivery quantity of the injection pump to the fuel requirement of the diesel engine.
In supercharged diesel engines, it is known to match the delivery or full-load quantity to the supercharge pressure. As the supercharge pressure available in the lower speed range is lower and consequently the weight of the air charge in the engine cylinder is less, the full-load quantity is matched to the reduced air weight by the supercharge-pressure-dependent adaptor. In other words, the delivery quantity is reduced or negatively adapted in the lower speed range.
Such a supercharge-pressure-dependent adapting device is disclosed in German Offenlegungsschrift No. 3,137,145. By means of this adapting device (FIG. 2, between C and a point D on the full-load characteristic curve), the full-load quantity is adapted to the supercharge pressure, which at first is too low.
An object of the present invention is the provision of an adapting device of the general type mentioned above, which is in operative connection with the injection pump governor such that it exhibits an improved torque profile through simple constructive means. Another object of the present invention is the provision of an improved adapting device which functions without exerting an influence on the supercharge pressure-dependent adaptation acting below the full-load characteristic curve.
These and other objects of the present invention are attained by adapting means for providing adjusting full load stop means when supercharge pressure force is applied to control rod means.
In conjunction with the standard, so-called negative adaptation, a further adaptation which acts independently of the negative adaptation is thus attained in a simple manner. In the torque performance graph, this means that the torque profile does not fall from maximum torque at increasing speed but is maintained over a certain speed range. This has an advantageous effect on the fuel consumption, because the power output remains at least approximately constant over a certain range as will be explained in the detailed description. Because of the special torque profile, it is possible to drive without changing gears frequently.
In one embodiment, a control rod travel characteristic curve is obtained which constantly increases from the adapting end-point of the negative adaptation up to the rated speed. In another embodiment, the control rod travel characteristic curve increases at a distance from the adapting end point of the negative adaptation up to the rated speed. In a further development adjustment of the adapting devices, adjusting work, for example, raising or lowering the full-load level, can be easily accomplished due to the special location of the second adapting device in conjunction with the first adapting device.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.